Disk drive and data management

The seasoned user will be aware that a computer system comprises a number of disks and drives, used for storing data which mainly consists of pictures downloaded from the internet. The computer's hard disk usually contains the operating system such as Microsoft Windows, as well as programs and the user's own dubious file collection.

Other drives include the generically-termed optical drive, meaning the CD-ROM, DVD or Blu-ray <cough> drive, plus USB 'thumb' drives. Some systems may have more than one physical hard disk inside, or may use an external USB-connected hard disk for storing data.

The computer's internal hard disk is generally considered to be the C: drive, although in truth the letter really refers to a partition on the hard disk. Although most users have a C: partition which is about the same size as the actual hard disk, say 250GB, it is possible to have multiple partitions on the same hard drive, such as a physical hard disk with a 30GB C: partition and a 220GB D: partition. The optical drive is then displaced from being the D: drive to becoming the E: drive, by default.

In theory a user could have 24 partitions named C: to Z: (A: and B: are reserved for the well-overdue-for-extinction floppy drive) although this would be unnecessary and some drive letters need to be reserved for USB drives, network drives and other external storage devices.

In the above example the system has two physical internal hard disks, Disk0 and Disk1 and an optical drive, referred to variously as CD-ROM0/DVD/Drive V:.

Disk0 (computers start counting from 0) has one single 298GB partition for data and is referred to as U: drive.

Disk1 is around 228GB and has four partitions, C;, D:, E: and F:. Windows boots from C: which also contains the installed programs. The other partitions are used for storing data and labelled accordingly. Note that from Windows Explorer's point-of-view, the system will appear to have 5 drives C: -> F: plus U: and an optical drive. Once formatted, Windows treats the partitions as if they are separate drives.

Separating out the data

Having one single partition which contains the operating system and programs, as well as user data becomes problematic when the operating system needs to be reinstalled, either due to problems (a reinstall can often fix things) or due to a new version of the OS such as Windows7. A common routine during an OS installation is to format the partition, which removes all previous files including user data such as documents, images, media, etc.

This is where the magic happens on a dual or multi partition system. Windows installs and boots from drive C: and programs also live here, typically in C:\Program Files\.. The trick is to make sure that user data goes on another partition such as D: and not on the C: drive, typically in C:\My Documents. That way when it comes time to reinstall Windows, the C: drive gets trashed in the format but all those essential files don't get thrown out with the bathwater and are still in fact, languishing untouched on the D: drive.

Although it's a pain in the arse losing the installed programs, they can be added from their install discs after Windows is loaded and again, the reinstallation can fix previous problems. However the user's own data can be irreplaceable. Note that this is not a reason not to back up user data - copies of important files still need to kept in a separate place such as burned to disc or copied to a file server on a network.

Where to from here?

So far things have been kept relatively introductory with a minimum of techno talk - yes, really. At this point some readers have got the message and will sally forth into the cyberwilderness, doing the right thing and spreading the good word. However those of a more rabid technical propensity may find themselves gagging for more detail.

Such readers are encouraged to seek more understanding by referring to further, erstwhile works dispersed by the author, including Hard Disk Partitioning Theory which admittedly, is starting to look somewhat dated. Nevertheless the principles have changed little, even though the average user wouldn't be seen dead with a 10GB hard disk in their possession; after all, such capacities are the stuff of USB drives in today's modern world.

Moving data - the next stages

The next part to separating data from system files is to create a data partition. This is described in easy-to-follow steps in the next article Managing disk partitions.

The final stage in giving your data somewhere better to live is moving the My Documents folder onto the D: drive. See Move the My Documents folder for the lowdown.